Under the vertical to be determined (by this technical solution) we will mean the gravitational vertical being the direction wherein the plummet (pendulum) would be located (positioned) only under the influence of the field of gravitation of the Earth (virtually, it being in non-rotating state).
At present, on the vehicles two methods are mainly used for determining the vertical: radial and inertial [1].
In both methods use is made of the gyroscope or stabilization platform, the gyro scopes being located whereon. Herewith, the signals are sent on the said gyroscope or the said platform in the form of the moments making them precession (rotate) at an angular speed of the rotation of the vertical of the place of location. The main difference of the said methods is in the method of forming the signals mentioned.
In the radial method the said signals are given off by the pendulum devices (or accelerometers), and in the inertial method use is made of the signals integrals of the said accelerometers.
The pendulum device (like an accelerometer) is considered to be subjected to harmful influence of the mutually perpendicular components aη, aξ, aζ of the absolute acceleration vector. Therefore, the radial method is used only for piloting but not for the navigation purposes. The vertical component aη is directed along the vertical η, and the components aξ and aζ are located in the horizontal plane and are acting along the horizontal axes ξ and ζ.
Let's assume that the component aη will be called the vertical acceleration, and the horizontal component aζ—longitudinal acceleration, and the horizontal component aζ—lateral acceleration, correspondingly.
In the inertial method, with the Shuler's non-disturbance condition observed, any harmful influence of the horizontal progressive acceleration is eliminated. This method is used not only for piloting but also for the navigation purposes. The inertial method is implemented in the gyro stabilization platform (GSP), wherein the said platform is stabilized in the horizontal position (in the horizontal plane). In the gyro stabilization platform (GSP) stabilization is performed along two channels (concerning two axes), even in those cases when it is not required. For example, when the stabilization in one channel (particularly, regarding longitudinal or cross-section axis of the moving object) is performed with the help of some additional means (using the skyline, movement along radio glissade, etc.).
This application relates mainly to the solution of the one-channel determination of the vertical, on the base whereof there will be provided, in brief, the two-channel device for the vertical determination, comprising a suspension with the platform stabilized in the horizontal position.
The main units of the GSP of one (from the two) channel are considered to be a gyroscope (gyroscopes), an accelerometer, erection mechanism (positioned on the platform) and an integrator (integrators) connected to each other.
The gyroscopic platform (GSP) is considered to have significant drawbacks:
long-lasting initial orientation (for more precise orientation tens of minutes are required);
for making the GSP, the gyroscopes, in particular, so strict requirements are to be met in terms of accuracy that in industry the said requirements cannot often be met;
the noticeable dependence of the accuracy of operation on the vertical centripetal and Coriolis accelerations as well as other disturbing factors (vibrations, temperature changes and others);
the necessity of fulfilling the Shuler's non-disturbance condition which is sure only for a certain flight altitude and is considered to exclude the opportunity of the quality improvement of adjustment (stability) through internal means (the signals of other sources are required);
with the negative vertical acceleration the signals of accelerometers can be, while tilting, (and the latter is said to practically always occur) intolerably big and, moreover, can cause considerable avalanche-like deflection of the platform from the horizontal position;
considerable complexity, weight, unhandiness, cost;
determination is made of not the gravitational vertical caused by the gravitational force but the vertical caused by the gravity force.
The closest analogue (prototype) of the technical solution to be provided is the device [2] to have been formerly proposed and patented by the authors. The said prototype in one channel comprises, as it is stated from its claims, the tilting angular sensor, the linear acceleration determiner positioned on the stabilization platform, the treatment unit and the unit of adjusting the platform into horizontal position. This adjustment unit receiving the signals from the said sensor and the said determiner is said to turn the said platform till superimposing their output signals. The present prototype has for its object to remove the above drawbacks of the GSP, however, only with the positive vertical acceleration aη (the vertical component of the absolute acceleration vector). Besides, like in the GSP, in the said prototype no harmful influence (on the operation accuracy) of the vibrations is prevented to the right degree. The negative vertical acceleration is considered to affect the said prototype in the same harmful way as it does on the said GSP. Therefore, with the negative vertical acceleration the application of the said prototype (as well as the GSP) might become impossible.
Meanwhile, the cases of the negative vertical acceleration (aη<0) do occur in practice, particularly, with the vibrations (the ones when there are even cases |aη|>>g, where g—free falling acceleration), with moving down towards the Earth (for example, rockets, spacecrafts) with |aη|>g, in “the air pockets”.
In addition, with the turned-down position (for example, of an aircraft) applying the prior art for determining the vertical is said to be possible only through performing special commutation (for example, the one to be used in the gyro horizon), which is also the disadvantage of the said solutions, particularly, herewith non-interruption of the readings being avoided.
In addition, the claims of the prototype [2] are considered to be wrong by definition. It is accounted for the fact that in the said claims use is made of the determiner of allegedly “linear acceleration”. But it is well-known that by definition the linear acceleration is directed at a tangent to the trajectory of the movement. And the said determiner is said to react particularly, on the centripetal acceleration as well, and, however, due to that, it doesn't determine the linear acceleration. Therefore, the prototype [2] cannot be opposed to (compared to) the prior art and for the same reason, the technical solution to be provided.
The present technical solution comprehends determining the gravitational vertical, increasing the accuracy and broadening the field of art, particularly, with acting of both positive and negative vertical acceleration; simplifying, lessening the weight, reducing the cost and lessening the construction sizes (more compact). Therefore, the said solution is considered to be universal.